DETERMINING THE SHAPE AND ORIENTATION OF A BOREHOLE

摘要

A method and apparatus (10) are provided for estimating the cross-sectional shape and orientation of an earth borehole (12) and the motion of a tool therein. The method and apparatus involve measuring the distance (30) from the tool to the borehole wall at a plurality of locations around the periphery of the tool and fitting those measured distances to a predetermined shape function using a nonlinear parameter estimation technique to minimize the error between the estimated shape of the borehole and the measured distances. The method and apparatus may be used to estimate elliptical and higher order borehole shapes. Additionally, the method and apparatus may be used while drilling the borehole.